The use of laser scanning bar code symbol reading engines is well known in the art. Applications include: hand-held products; reverse-vending machines; and the like.
Currently, various types of laser scanning mechanisms have been developed for scanning laser beams across bar code symbols. Such laser scanning mechanisms include shaft-based laser scanning mechanisms; hinge-based laser scanning mechanisms; torsional-based laser scanning mechanisms; and flipper-based laser scanning mechanisms.
Conventional shaft-based scanning mechanisms suffer from a number of shortcomings and drawbacks. In particular, prior art shaft-based scanning assemblies suffer from friction-related uncertainty and reliability problems. When using a magnet to generate the return force, the resonant laser scanning system becomes unstable when subjected to excessive external forces.
Conventional silicone hinge-based laser scanning assemblies suffer from scan motion imprecision, due to the fact that such prior art scanning assemblies do not have a fixed scanning axis. Consequently, mirror scan mirror motion does not undergo perfect rotation, and thus, scan beam motion does not follow near ideal linear scanning motion. Also, when subjected to high G forces, additional motion limiters are required to prevent excessive motion. However, these extra motion limiters add complexity to the final laser scanning assembly.
Also, in conventional silicone hinge-based laser scanning assemblies, the moving part (i.e. rotor structure) which holds the scan mirror and permanent magnet is typically a subassembly of flexible and rigid parts, made from materials such as silicone and thermoplastic, or silicone and copper.
Conventional flipper-based laser scanning mechanisms, used generate scan lines in a laser based barcode scanner, also suffer from a number of shortcomings and drawbacks. In particular, stability of such laser scanning mechanisms directly affects the performance of the laser scanner.
Thus, there is great need in the art for new and improved laser scanning assemblies, which avoid the shortcomings and drawbacks of the prior art scanning methods and apparatus.